Question

Problem:

Plot the egg holder function and find the global optimizer in Matlab

Eggholder function:

Y= -(u2+47)*sin(sqrt(abs((u2)+(u1/2)+(47)))) - (u1)*sin(sqrt(abs((u1)-(u2+47))))

where u equals x

Below is my code and the picture of the graph I got. I know for a fact that it's wrong but don't know how to fix it.

Figure 1 Desktop File Edit Tools Window Help View Insert AE x105 1 0.5 0 -0.5 -1 600 400 600 200 400 200 -200 -200 -400 -400 -600 -600

<

x1=[-600:10:600];

x2=[-600:10:600];

[u1, u2] = meshgrid(x1, x2);

term1=-(u2+47)*sin(sqrt(abs((u2)+(u1/2)+(47))));

term2=-(u1)*sin(sqrt(abs((u1)-(u2+47))));

y=term1+term2;

figure

surf(u1,u2,y)

>

Please show all work and explain what you're doing so that I can understand the process.

Answer 1

There is just slight modification in the code provided here. Since x1 and x2 are array, while multiplying, we have to use (.*) for element wise multiplication in the expression of term1 and term2.

Below is the corrected code :

%To create the meshgrid of two variables x1 and x2 varying from -600 to 600
%with an interval of 10
[x1, x2] = meshgrid(-600:10:600, -600:10:600);

%First Term of eggholder function
term1= -(x2+47).*sin(sqrt(abs((x2)+(x1/2)+(47))));
%Second Term of eggholder function
term2= -(x1).*sin(sqrt(abs((x1)-(x2+47))));

y=term1+term2;

figure
% Surface Plot
surf(x1,x2,y)
title('Eggholder Function')

Eggholder Function 1500 1000 500 0 -500 -1000 -1500 600 600 400 400 200 200 200 200 400 400 600 -600